Are buntings good indicators of agricultural intensity?

Numerous countries in Western Europe have experienced a dramatic decline in their yellowhammer (Emberiza citrinella), corn bunting (E. calandra) and ortolan bunting (E. hortulana) populations. Data from the Common Breeding Bird Survey in Poland were used to examine the response of bunting population densities to agricultural intensification at different spatial scales. The results suggested that buntings preferred habitats that differed from those that are characteristic of Western Europe. Although yellowhammers preferred extensive agricultural areas, corn and ortolan buntings reached maximum densities in intensively managed farmland. In addition, both species preferred different woodlot structures and crop types. All studied bunting species exhibited non-linear responses to agricultural intensification. Under certain conditions, agricultural intensification may increase bunting population densities (especially for corn buntings). More generally, we provided a description of how complex patterns of bunting occurrence in agricultural landscapes may serve as indices of agricultural intensification in Europe.